Corals grain size

Figure 11.3 Outcrop and hand specimens of beachrock. (A) Freshly broken piece of beachrock with mostly sand-sized constituent particles. Kuramathi island, Rasdu Atoll, Maldives. Height of picture is 5 cm. (B) Beachrock with mostly cobble-sized fragments of coral. Long Cay, Glovers Reef, Belize. (C) Close-up of fossil beachrock outcrop from Ras Al-Julayah, southern Kuwait. Note how fine-grained layers are better cemented than coarse-grained ones. (For overview of outcrop see Figure 11.9A.)...

Figure 8. a) Number of soil grains that reached the sea floor by the end of the period (0400 JST on October 25, 2011) calculated by the particle tracking analysis described in section 2.5 and coverage of (b) tabular coral and (c) branching coral at Stations 1-26. The sizes of grains counted in (a) were 1, 3, and 5 pm in diameter. The number of soil grains at Stations 17 and 18 in (a) were over 1000 (after [18]). 

The trace elemental composition for carbonate was determined by WDS on a JEOL 733 electron microprobe. Accelerating voltage was 15 kV sample current was stabilized at 12 nA on brass spot size was lOjim count time for all elements was 20 s, except for Sr, analysed for 60 s standards were cal-cite (Ca), dolomite (Ca, Mg), coral (Sr) and siderite (Fe, Mn) beam placement was in every case guided by the back-scattered electron image Si was routinely counted by WDS in order to monitor possible contamination from adjacent silicate grains not revealed by the back-scattered image totals between 97 and 103 wt% were accepted. Detection limits are approximately 340 ppm for Mg, 450 ppm for Fe, 310 ppm for Mn and 185 ppm for Sr. 

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